(in PostScript graphics only)
Points in a scatter plot can be connected by arrows (or line segments)
by giving an ARROWS specification.
Its simplest form is
ARROWS=A
where A=[a_ij] is an incidence matrix saved as a matrix file and
a_ij=1 means that points of observations i and j are to be connected
and a_ij=0 that points i and j are not to be connected.
It is assumed that when the data set has n observations, A is an
m x n (m<=n) matrix. Thus restrictions by IND, CASES etc. are not permitted.
The general form of ARROWS is
ARROWS=matrix,gap,type,alen,angle
where default
matrix: incidence matrix (MAT file) -
gap: distance from end points (in plotting units) 0
type: 0=no arrow, 1=end arrow, 2=start arrow, 3=both, 4= <--> 0
corresponding negative value = filled arrow head
alen: length of arrow (in plotting units) 20
angle: angle (sharpness) of arrow (in radians) pi/6
To give a possibility to configure each connection individually
(i.e. variation in line width, type, and color as well as in arrow type),
the non-zero elements can be presented as decimal numbers of form
a_ij = swww.tacc
where www (one or more digits) is the line width as multiple of
0.24 Points, 0.24(Point:mm)=0.084666...,
t (one digit) is index of line type (LINETYPE?),
a (one digit) is arrow type (see previous page),
cc (two digits) is the index of color given by FILL spec.,
s (sign) '-' gives filled arrow head(s).
For example, a_ij=-5.0304 implies an arrow having width 5*0.24=1.2 Points,
solid line type (0), arrow type >---> (3), filled arrow heads (-), and
color (4) specified by FILL(-4)=c,m,y,k (See PSCOLOR?).
Examples are given in
http://www.survo.fi/tmp/VectorDiagrams.pdf
and an edit file containing these examples is
http://www.survo.fi/tmp/ARROWS.EDT
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